In a typical lipstick case, in order to enable the holder cup to be moved between an advanced and a retracted position, the case is provided with an inner sleeve and an outer sleeve which rotate with respect to each other. The inner sleeve has a wall and a longitudinal track extending through the wall. The outer sleeve is placed about the inner sleeve so as to be able to rotate with respect to the inner sleeve. The outer sleeve has an inner wall, an outer wall, and a helical groove which extends along a substantial length of the inner wall. The holder cup is fitted into the inner sleeve. The holder cup is provided with at least one lug which extend through the longitudinal track of the inner sleeve to engage the helical groove of the outer sleeve. When the inner and outer sleeves are rotated, the lug of the holder cup follows the path defined by the longitudinal track and the helical groove, thereby moving the holder cup between an advanced and a retracted position.
In order to enable the holder cup to easily move between an advanced and a retracted position, the holder cup is typically provided with a pair of opposing lugs. Whether the holder cup has one lug, or a pair of opposing lugs, certain problems arise during its operation. Namely, the use of only one lug, or a pair of lugs, creates an instability of the cup. As the inner and outer sleeve of the case are rotated with respect to each other, a torque is applied to the lug(s) of the holder cup. This torque advances and retracts the cup, and also causes the cup to pivot about the axis of the lug(s), thus causing the cup to skew as it travels within the case.
In order for the case to function properly, the cup must be able to move between the advanced and retracted positions without undue interference or resistance. Therefore, a certain space, however small, is required between the holder cup and the inner sleeve, which space varies due to manufacturing tolerances of the individual components of the case itself. This space, and the variations in its size, is what enables the holder cup to pivot. Typically, the stick product is an elongated cylinder which is held within the holder cup at the base, thereby leaving the majority of the stick extending out of the holder cup. Because the lugs are placed on the holder cup, a slight pivot about the axis of the lugs will be exaggerated near the tip of the stick, and typically will be enough to cause the product within the holder cup to contact the inner surface of the inner sleeve, thereby deforming the product and interfering with the function of the case.
The purpose of the present invention is to provide a stick product case which will reduce the skew of the holder cup while continuing to provide simple operation of the case.
Another purpose of the present invention is to provide a stick product case that is simple to manufacture.
Further, it is a purpose of this invention to provide a stick product case which is a relatively simple item that avoids interference with package aesthetics.